well, I just saw the next article about clerics, and it confirms that clerics can, in fact, use a higher level spell slot to prepare a lesser spell:

A cleric's spell slot can hold a spell of its level or of a lower level.

A cleric can prepare a lower-level spell in a higher-level slot, just as any other spellcaster can. If the cleric's Wisdom score won't allow her to prepare spells in her higher-level slots, she still can use those slots for lower-level slots. For example, a 9th-level cleric has 4th-level spell slots available. If the cleric has a Wisdom score of only 13, however, she can prepare and cast up to 3rd-level spells only. She can prepare spells of 3rd level or lower in her otherwise unusable 4th-level spell slots. Although the text on page 32 in the Player's Handbook seems to imply that a domain spell slot can hold a spell of its own level only, there's no good reason to bar a cleric from preparing a lower-level spell from one of her domains for that slot.

Like other spellcasters, clerics also can prepare spells using metamagic feats, which make those spells use higher-level spell slots. To prepare or cast a spell modified with most metamagic feats, the cleric's Wisdom score must be at least equal to 10 + the spell's unmodified level. For example, a cleric with a Wisdom score of 14 can use a 5th-level spell slot to prepare a 4th-level spell modified with the Enlarge Spell metamagic feat (which makes the spell use a slot one level higher than normal). The Heighten Spell metamagic feat actually raises the spell's level, as noted in the D&D FAQ. To prepare or cast a spell modified with the Heighten Spell feat, the cleric's Wisdom score must be equal to 10 + the spell's modified level

but what of the other classes that aren't magic users? they have to deal with the same limitations with no way to circumvent them for extra benefits A fighter for example, have to deal with having a low strength, and if a Rogue has a below average Dex, then they have to deal with it.

so why should the casting classes (and I would presume that this would apply to the other casting classes) have a way to weasel around this limitation?

you'd have to ask how did they earn that 35000gp....however they did it, unless the DM was Monty Hauling the campaign, they earned it, the same way a player can earn a stat boost every 4 levels

and the restrictions that I would place on buying stat boosting items would be where they were buying them (if the city/town/etc. doesn't have a wiz/clr/sor who can make them, or can't afford to make them) and a limit on how much of a boost can be placed in an item (never anything higher than +5, and anything above +2 are rare items)

but if they can find them (in game) and afford them then i wouldn't have a problem with it.